Field of the Invention
The present invention relates to a wireless charging device and charging method thereof, especially to a wireless charging device for charging a plurality of wireless power receiving apparatus and charging method thereof.
Description of the Prior Art
FIG. 1 is a schematic diagram showing the prior-art wireless charging device. The shown wireless charging device comprises a power transmitting end 10 and a power receiving end 20. The power transmitting end 10 comprises a transmitting-end coil 11 and a transmitting-end ferrite plate 12. The power receiving end 20 correspondingly comprises a receiving-end coil 21 and a receiving-end ferrite plate 22. When the power receiving end 20 is in proximity of the power transmitting end 10 and electrical current flows through the transmitting-end coil 11 to generate electromagnetic field, the receiving-end coil 21 of the power receiving end 20 will generate electrical current induced by the electromagnetic field generated by the transmitting-end coil 11 to achieve wireless charging.
However, the prior-art wireless charging device generally charges other electronic device in one by one manner and the power receiving end 20 is laid down on the wireless charging device. The electronic device cannot be charged by the wireless charging device when the other electronic device is placed on the wireless charging device and still charging. More particularly, the electromagnetic field of the power transmitting end 10 propagates along upward direction as shown in FIG. 1 such that device of the power receiving end 20, which is laid upon the platform of the power transmitting end 10, will receive the electromagnetic field of the power transmitting end 10. The electromagnetic field of the power transmitting end 10 cannot propagate outward unless the platform of the power transmitting end 10 is large enough. However, a large platform of the power transmitting end is bulky and not practical.